Figures 2 to 8 (an investigation of the sand impounded by major harbor structures 

 such as the Huron and Fairport Harbor jetties is not included in the survey). 

 Data consist of 690 kilometers of reflection profiles (taken in August 1977) and 

 58 cores (taken in August 1978) ranging from 0.67 to 6.1 meters in length. About 

 25 percent of Ohio's open lake part of Lake Erie (8,960 square kilometers) was 

 covered by the seismic reflection survey. These data were supplemented by pre- 

 viously published lake studies. Vertical control was obtained from National 

 Ocean Survey (NOS) water level gage data; water depths are referenced to low 

 water datum (LWD) , 173.3 meters above mean water level at Father Point, Quebec 

 (International Great Lakes Datum, 1955) for Lake Erie. Mean lake level in both 

 August 1977 and 1978 was about 1 meter above LWD. 



This report is basically a reconnaissance effort; seismic line spacing and 

 .orientation and core spacing density preclude a detailed evaluation of the nature 

 .of the offshore sand deposits. However, the more detailed seismic reflection 

 line spacing and the greater number of vibracores collected in the Fairport and 

 ^Lorain-Vermilion areas allow general estimates to be made of the sand volumes of 

 these areas . 



2. Geographic and Geologic Setting . 



The shore from Toledo to Conneaut is characterized by a flat to gently 

 rolling terrain which slopes to the north and is dissected by many rivers and 

 creeks which flow toward Lake Erie. The principal rivers are the Maumee, the 

 Toussaint, the Portage, the Sandusky, the Huron, the Vermilion, the Black, the 

 Rocky, the Cuyahoga, the Chagrin, the Grand, the Ashtabula, and the Conneaut, 

 some of which have major harbors at their mouths. A large part of the shore 

 is developed, particularly the densely populated area between Cleveland and 

 Sandusky which consists mostly of urban and suburban communities. 



Shore deposits consist primarily of glacial drift and lacustrine clay; rock 

 is exposed along the shore at Marblehead and along much of the shore between 

 Vermilion and Cleveland. These deposits have formed banks, slopes, and bluffs 

 that average about 10 meters in height, and range from the 1-meter-high clay 

 banks near Toledo to the 21-meter-high till bluffs near Conneaut. Beaches which 

 front the shore are generally narrow (<15 meters wide) and are commonly discon- 

 tinuous because of limited sand in the littoral system due to manmade structures 

 or natural deficiencies. Just offshore, the lake bottom slopes are gentle and 

 water depths 100 meters from the shoreline are generally no more than -2 meters. 

 The nearshore lake bottom is commonly composed of bedrock, till, or sand. Far- 

 ther offshore the bottom is nearly flat, covered mostly by glacial and post- 

 glacial fine-grained lacustrine deposits. 



3. Previous Studies . 



Verber (1957) and Hartley (1961) conducted the first comprehensive studies 

 of bottom sediments off the Ohio part of the central and western Lake Erie 

 basins. Bottom grab samples were taken on 1.6- or 3.2-kiloraeter grids, with 

 some subbottom sampling by coring or jetting. Detailed echo sounding and bottom 

 sampling to a depth of about 1.0 meter had previously been done in the Lorain- 

 Vermilion and Fairport Harbor sand dredging areas in a cooperative effort by the 

 U.S. Army Corps of Engineers and ODGS (Beach Erosion Board, 1952). The shore 

 and nearshore deposits within about 600 meters of the shoreline were also mapped 

 in the 1970 's by ODGS as part of their county shore erosion studies (e.g.. Carter, 

 1976, and Benson, 1978). 



8 



